Sanding grits for plywood with a clear finish

[jc]

I have good results with Target 6000 and 9000sc.

 

[Good77696e]

Is your paper staying clean? A single buildup that you don't resand with clean paper can cause deep scratches that show in the finish. You may need to wait longer for a wb finish to cure before you sand.
[/quote]

No it is not, maybe this is my problem. I will keep this in mind for the next time, thank-you.

 

[Good77696e]

I think you should re-coat sooner.
Under ideal conditions you should be able to apply a new coat after an hour or two and you don't need to sand much but rather take the "nibs" off. 
This way you won't introduce any problems that Tommy is referring to.
After 24 hrs., polyurethane like EM9000 is on it's way to curing and needs to be completely sanded so the next coat binds properly.
I also use a 3M scotch brite pad rather than sandpaper to get rid of nibs etc. and then I wipe any powder residue with a clean cloth.

BTW, how long did you wait after spraying your first coat of polyurethane over the stain?

Tim
[/quote]

I think I waited about a day after the stain went on before I sprayed the poly. I'm going to try the things that you are suggesting and see how I make out. First I think I will go get a new sander. I have a piece that I want to sand off the stain and try it again.